This invention relates to methods of and apparatus for transmitting stereophonic audio signals. This invention relates also to apparatus for reproducing stereophonic signals.
The Bluetooth standard allows for devices to communicate with each other in a wireless fusion with certain defined channels, including three 64 kb per second SCO channels. Each channel can carry sampled audio signals having a bandwidth of a 4 kHz with 8 bit samples. However, 4 kHz is regarded as not being suitable for use with portable hi-fi equipment, although it is regarded as being sufficient for carrying voice signals.
It is known to reduce the amount of digital data required to represent stereophonic sound signals using coders according to the MPEG-1 standard. Stereophonic signals reconstructed after MPEG-1 compression tend to be of a very high quality. However, MPEG coders and decoders are not cheap to produce, and they tend to have quite high power consumption. As a result, it is desirable to avoid their use in portable, battery-operated equipment.